"use strict";

const address = require("address");
const fs = require("fs");
const path = require("path");
const url = require("url");
const chalk = require("chalk");
const detect = require("detect-port-alt");
const isRoot = require("is-root");
const prompts = require("prompts");
const clearConsole = require("./clearConsole");
const formatWebpackMessages = require("./formatWebpackMessages");
const getProcessForPort = require("./getProcessForPort");
const forkTsCheckerWebpackPlugin = require("fork-ts-checker-webpack-plugin");

const isInteractive = process.stdout.isTTY;

function prepareUrls(protocol, host, port, pathname = "/") {
  const formatUrl = (hostname) =>
    url.format({
      protocol,
      hostname,
      port,
      pathname,
    });
  const prettyPrintUrl = (hostname) =>
    url.format({
      protocol,
      hostname,
      port: chalk.bold(port),
      pathname,
    });

  const isUnspecifiedHost = host === "0.0.0.0" || host === "::";
  let prettyHost, lanUrlForConfig, lanUrlForTerminal;
  if (isUnspecifiedHost) {
    prettyHost = "localhost";
    try {
      // This can only return an IPv4 address
      lanUrlForConfig = address.ip();
      if (lanUrlForConfig) {
        // Check if the address is a private ip
        // https://en.wikipedia.org/wiki/Private_network#Private_IPv4_address_spaces
        if (
          /^10[.]|^172[.](1[6-9]|2[0-9]|3[0-1])[.]|^192[.]168[.]/.test(
            lanUrlForConfig
          )
        ) {
          // Address is private, format it for later use
          lanUrlForTerminal = prettyPrintUrl(lanUrlForConfig);
        } else {
          // Address is not private, so we will discard it
          lanUrlForConfig = undefined;
        }
      }
    } catch (_e) {
      // ignored
    }
  } else {
    prettyHost = host;
  }
  const localUrlForTerminal = prettyPrintUrl(prettyHost);
  const localUrlForBrowser = formatUrl(prettyHost);
  return {
    lanUrlForConfig,
    lanUrlForTerminal,
    localUrlForTerminal,
    localUrlForBrowser,
  };
}

function printInstructions(appName, urls, useYarn) {
  console.log();
  console.log(`You can now view ${chalk.bold(appName)} in the browser.`);
  console.log();

  if (urls.lanUrlForTerminal) {
    console.log(
      `  ${chalk.bold("Local:")}            ${urls.localUrlForTerminal}`
    );
    console.log(
      `  ${chalk.bold("On Your Network:")}  ${urls.lanUrlForTerminal}`
    );
  } else {
    console.log(`  ${urls.localUrlForTerminal}`);
  }

  console.log();
  console.log("Note that the development build is not optimized.");
  console.log(
    `To create a production build, use ` +
      `${chalk.cyan(`${useYarn ? "yarn" : "npm run"} build`)}.`
  );
  console.log();
}

function createCompiler({
  appName,
  config,
  urls,
  useYarn,
  useTypeScript,
  webpack,
}) {
  // "Compiler" is a low-level interface to webpack.
  // It lets us listen to some events and provide our own custom messages.
  let compiler;
  try {
    compiler = webpack(config);
  } catch (err) {
    console.log(chalk.red("Failed to compile."));
    console.log();
    console.log(err.message || err);
    console.log();
    process.exit(1);
  }

  // "invalid" event fires when you have changed a file, and webpack is
  // recompiling a bundle. WebpackDevServer takes care to pause serving the
  // bundle, so if you refresh, it'll wait instead of serving the old one.
  // "invalid" is short for "bundle invalidated", it doesn't imply any errors.
  compiler.hooks.invalid.tap("invalid", () => {
    if (isInteractive) {
      clearConsole();
    }
    console.log("Compiling...");
  });

  let isFirstCompile = true;
  let tsMessagesPromise;

  if (useTypeScript) {
    forkTsCheckerWebpackPlugin
      .getCompilerHooks(compiler)
      .waiting.tap("awaitingTypeScriptCheck", () => {
        console.log(
          chalk.yellow(
            "Files successfully emitted, waiting for typecheck results..."
          )
        );
      });
  }

  // "done" event fires when webpack has finished recompiling the bundle.
  // Whether or not you have warnings or errors, you will get this event.
  compiler.hooks.done.tap("done", async (stats) => {
    if (isInteractive) {
      clearConsole();
    }

    // We have switched off the default webpack output in WebpackDevServer
    // options so we are going to "massage" the warnings and errors and present
    // them in a readable focused way.
    // We only construct the warnings and errors for speed:
    // https://github.com/facebook/create-react-app/issues/4492#issuecomment-421959548
    const statsData = stats.toJson({
      all: false,
      warnings: true,
      errors: true,
    });

    const messages = formatWebpackMessages(statsData);
    const isSuccessful = !messages.errors.length && !messages.warnings.length;
    if (isSuccessful) {
      console.log(chalk.green("Compiled successfully!"));
    }
    if (isSuccessful && (isInteractive || isFirstCompile)) {
      printInstructions(appName, urls, useYarn);
    }
    isFirstCompile = false;

    // If errors exist, only show errors.
    if (messages.errors.length) {
      // Only keep the first error. Others are often indicative
      // of the same problem, but confuse the reader with noise.
      if (messages.errors.length > 1) {
        messages.errors.length = 1;
      }
      console.log(chalk.red("Failed to compile.\n"));
      console.log(messages.errors.join("\n\n"));
      return;
    }

    // Show warnings if no errors were found.
    if (messages.warnings.length) {
      console.log(chalk.yellow("Compiled with warnings.\n"));
      console.log(messages.warnings.join("\n\n"));

      // Teach some ESLint tricks.
      console.log(
        "\nSearch for the " +
          chalk.underline(chalk.yellow("keywords")) +
          " to learn more about each warning."
      );
      console.log(
        "To ignore, add " +
          chalk.cyan("// eslint-disable-next-line") +
          " to the line before.\n"
      );
    }
  });

  // You can safely remove this after ejecting.
  // We only use this block for testing of Create React App itself:
  const isSmokeTest = process.argv.some(
    (arg) => arg.indexOf("--smoke-test") > -1
  );
  if (isSmokeTest) {
    compiler.hooks.failed.tap("smokeTest", async () => {
      await tsMessagesPromise;
      process.exit(1);
    });
    compiler.hooks.done.tap("smokeTest", async (stats) => {
      await tsMessagesPromise;
      if (stats.hasErrors() || stats.hasWarnings()) {
        process.exit(1);
      } else {
        process.exit(0);
      }
    });
  }

  return compiler;
}

function resolveLoopback(proxy) {
  const o = url.parse(proxy);
  o.host = undefined;
  if (o.hostname !== "localhost") {
    return proxy;
  }
  // Unfortunately, many languages (unlike node) do not yet support IPv6.
  // This means even though localhost resolves to ::1, the application
  // must fall back to IPv4 (on 127.0.0.1).
  // We can re-enable this in a few years.
  /*try {
     o.hostname = address.ipv6() ? '::1' : '127.0.0.1';
   } catch (_ignored) {
     o.hostname = '127.0.0.1';
   }*/

  try {
    // Check if we're on a network; if we are, chances are we can resolve
    // localhost. Otherwise, we can just be safe and assume localhost is
    // IPv4 for maximum compatibility.
    if (!address.ip()) {
      o.hostname = "127.0.0.1";
    }
  } catch (_ignored) {
    o.hostname = "127.0.0.1";
  }
  return url.format(o);
}

// We need to provide a custom onError function for httpProxyMiddleware.
// It allows us to log custom error messages on the console.
function onProxyError(proxy) {
  return (err, req, res) => {
    const host = req.headers && req.headers.host;
    console.log(
      chalk.red("Proxy error:") +
        " Could not proxy request " +
        chalk.cyan(req.url) +
        " from " +
        chalk.cyan(host) +
        " to " +
        chalk.cyan(proxy) +
        "."
    );
    console.log(
      "See https://nodejs.org/api/errors.html#errors_common_system_errors for more information (" +
        chalk.cyan(err.code) +
        ")."
    );
    console.log();

    // And immediately send the proper error response to the client.
    // Otherwise, the request will eventually timeout with ERR_EMPTY_RESPONSE on the client side.
    if (res.writeHead && !res.headersSent) {
      res.writeHead(500);
    }
    res.end(
      "Proxy error: Could not proxy request " +
        req.url +
        " from " +
        host +
        " to " +
        proxy +
        " (" +
        err.code +
        ")."
    );
  };
}

function prepareProxy(proxy, appPublicFolder, servedPathname) {
  // `proxy` lets you specify alternate servers for specific requests.
  if (!proxy) {
    return undefined;
  }
  if (typeof proxy !== "string") {
    console.log(
      chalk.red('When specified, "proxy" in package.json must be a string.')
    );
    console.log(
      chalk.red('Instead, the type of "proxy" was "' + typeof proxy + '".')
    );
    console.log(
      chalk.red('Either remove "proxy" from package.json, or make it a string.')
    );
    process.exit(1);
  }

  // If proxy is specified, let it handle any request except for
  // files in the public folder and requests to the WebpackDevServer socket endpoint.
  // https://github.com/facebook/create-react-app/issues/6720
  const sockPath = process.env.WDS_SOCKET_PATH || "/ws";
  const isDefaultSockHost = !process.env.WDS_SOCKET_HOST;
  function mayProxy(pathname) {
    const maybePublicPath = path.resolve(
      appPublicFolder,
      pathname.replace(new RegExp("^" + servedPathname), "")
    );
    const isPublicFileRequest = fs.existsSync(maybePublicPath);
    // used by webpackHotDevClient
    const isWdsEndpointRequest =
      isDefaultSockHost && pathname.startsWith(sockPath);
    return !(isPublicFileRequest || isWdsEndpointRequest);
  }

  if (!/^http(s)?:\/\//.test(proxy)) {
    console.log(
      chalk.red(
        'When "proxy" is specified in package.json it must start with either http:// or https://'
      )
    );
    process.exit(1);
  }

  let target;
  if (process.platform === "win32") {
    target = resolveLoopback(proxy);
  } else {
    target = proxy;
  }
  return [
    {
      target,
      logLevel: "silent",
      // For single page apps, we generally want to fallback to /index.html.
      // However we also want to respect `proxy` for API calls.
      // So if `proxy` is specified as a string, we need to decide which fallback to use.
      // We use a heuristic: We want to proxy all the requests that are not meant
      // for static assets and as all the requests for static assets will be using
      // `GET` method, we can proxy all non-`GET` requests.
      // For `GET` requests, if request `accept`s text/html, we pick /index.html.
      // Modern browsers include text/html into `accept` header when navigating.
      // However API calls like `fetch()` won’t generally accept text/html.
      // If this heuristic doesn’t work well for you, use `src/setupProxy.js`.
      context: function (pathname, req) {
        return (
          req.method !== "GET" ||
          (mayProxy(pathname) &&
            req.headers.accept &&
            req.headers.accept.indexOf("text/html") === -1)
        );
      },
      onProxyReq: (proxyReq) => {
        // Browsers may send Origin headers even with same-origin
        // requests. To prevent CORS issues, we have to change
        // the Origin to match the target URL.
        if (proxyReq.getHeader("origin")) {
          proxyReq.setHeader("origin", target);
        }
      },
      onError: onProxyError(target),
      secure: false,
      changeOrigin: true,
      ws: true,
      xfwd: true,
    },
  ];
}

function choosePort(host, defaultPort) {
  return detect(defaultPort, host).then(
    (port) =>
      new Promise((resolve) => {
        if (port === defaultPort) {
          return resolve(port);
        }
        const message =
          process.platform !== "win32" && defaultPort < 1024 && !isRoot()
            ? `Admin permissions are required to run a server on a port below 1024.`
            : `Something is already running on port ${defaultPort}.`;
        if (isInteractive) {
          clearConsole();
          const existingProcess = getProcessForPort(defaultPort);
          const question = {
            type: "confirm",
            name: "shouldChangePort",
            message:
              chalk.yellow(
                message +
                  `${existingProcess ? ` Probably:\n  ${existingProcess}` : ""}`
              ) + "\n\nWould you like to run the app on another port instead?",
            initial: true,
          };
          prompts(question).then((answer) => {
            if (answer.shouldChangePort) {
              resolve(port);
            } else {
              resolve(null);
            }
          });
        } else {
          console.log(chalk.red(message));
          resolve(null);
        }
      }),
    (err) => {
      throw new Error(
        chalk.red(`Could not find an open port at ${chalk.bold(host)}.`) +
          "\n" +
          ("Network error message: " + err.message || err) +
          "\n"
      );
    }
  );
}

module.exports = {
  choosePort,
  createCompiler,
  prepareProxy,
  prepareUrls,
};
